Length dependence of active force production  in skeletal muscle

Rassier, Dilson E.; MacIntosh, Brian R.; Herzog, Walter

doi:10.1152/jappl.1999.86.5.1445

Cited by 345 publications

(293 citation statements)

References 82 publications

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“…The fact that maximum isometric force depends on muscle length has been well described in the literature 20 , but this fact alone does not explain the greater decrease in force production in the paretic lower limb compared to controls in our study. Muscle weakness, or the inability to generate normal levels of force, is a common consequence of stroke and has clinically been recognized as one of the limiting factors in physical function in the motor rehabilitation of stroke persons with hemiparesis 19 .…”

Section: Discussioncontrasting

confidence: 56%

Strength deficit of knee flexors is dependent on hip position in adults with chronic hemiparesis

Michaelsen¹,

Ovando²,

Bortolotti³

et al. 2013

Braz. J. Phys. Ther.

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| Background: The extent to which muscle length affects force production in paretic lower limb muscles after stroke in comparison to controls has not been established. Objectives: To investigate knee flexor strength deficits dependent on hip joint position in adults with hemiparesis and compare with healthy controls. Method: a cross-sectional study with ten subjects with chronic (63±40 months) hemiparesis with mild to moderate lower limb paresis (Fugl-Meyer score 26±3) and 10 neurologically healthy controls. Isometric knee flexion strength with the hip positioned at 90° and 0° of flexion was assessed randomly on the paretic and non-paretic side of hemiparetic subjects and healthy controls. Subjects were asked to perform a maximal isometric contraction sustained for four seconds and measured by a dynamometer. The ratio of knee flexor strength between these two hip positions was calculated: Hip 0°/Hip 90°. Also, locomotor capacity was evaluated by the timed up and go test and by walking velocity over 10 meters. Results: In subjects with hemiparesis, absolute knee flexion torque decreased (p<0.001) with the hip in extension (at 0°). The ratio of knee flexor torque Hip 0°/Hip 90° on the paretic side in hemiparetics was lower than in controls (p=0.02). Conclusions: Weakness dependent on joint position is more significant in the paretic lower limb of adults with hemiparesis when compared to controls. More attention should be given to lower limb muscle strengthening exercises in individuals with stroke, with emphasis on the strengthening exercises in positions in which the muscle is shortened.Keywords: stroke; lower extremity; muscle weakness; physical therapy; rehabilitation. HOW TO CITE THIS ARTICLEMichaelsen SM, Ovando AC, Bortolotti A, Bandini B. Strength deficit of knee flexors is dependent on hip position in adults with chronic hemiparesis. Braz J Phys Ther. 2013 Jan-Feb; 17(1):86-91. http://dx

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Section: Discussioncontrasting

confidence: 56%

Strength deficit of knee flexors is dependent on hip position in adults with chronic hemiparesis

Michaelsen¹,

Ovando²,

Bortolotti³

et al. 2013

Braz. J. Phys. Ther.

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“…Since the ER peak torque occurred when the shoulder was externally rotated, it can be inferred that the WMMA was more important for torque generation in this ROM and for plateau maintenance than was the length versus tension relationship represented by the curve of resultant force. It can also be noted that the peak torque and peak force did not occur at the same angles, since they depended on the length-tension relationship of the muscle and its respective moment arm 11 .…”

Section: Discussionmentioning

confidence: 97%

“…Since the muscles are slightly stretched, there is a contribution from the elastic elements of the muscles, to force production 21,22,23 . After this point, the force decreases because of the muscle shortening and because of the reduced possibility of forming new crossbridges 11,23,24 .…”

Section: Discussionmentioning

confidence: 99%

“…The force production capacity depends on several factors such as the length-tension relationship, the force-velocity relationship and the fiber recruitment (spatial and temporal summation). However, for maximum contractions at constant velocity, the force production capacity of the muscle depends on the muscle length and this "dependence" relates directly to the length-tension relationship of the sarcomere 11 . This relationship can be explained by the sliding filament theory 12,13 and the cross-bridge theory 14,15 .…”

Section: Introductionmentioning

confidence: 99%

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Critérios mecânicos para progressão de exercícios de rotação interna e externa do ombro no plano sagital

Toledo

Ribeiro

Loss

2007

Rev. bras. fisioter.

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Introduction: Knowledge of torque and force production capacity and moment arm patterns throughout the movement, and their influence on the torque produced, are essential for understanding human movement and may be of great use for controlling the overload imposed on the muscle-tendon structure. Objective: To present mechanical criteria for progression in internal rotation (IR) and external rotation (ER) exercises of the shoulder in the sagittal plane. Method: Six individuals were assessed using an isokinetic dynamometer and an electrogoniometer. From the data collected, the mean torque, mean resultant force and weighted mean moment arm were calculated using the SAD32 and Matlab ® software. Results: The angles at which the peak ER and IR torque occurred were -34° and 6º with values of 43 Nm and 69 Nm, respectively. The peaks for ER and IR muscle force were at 35º and -14º, and the values at these angles were 10227 N and 8464 N, respectively. The weighted mean moment arm for ER presented an increasing pattern over the whole range of motion (ROM) and the peak was at the end of the ROM, i.e. at -50º (0.91 cm). The weighted mean moment arm for IR was almost constant with its peak at 50º (0.96 cm). Conclusion: The mechanical criteria for progression in internal and external rotation exercises of the shoulder are torque, force and weighted mean moment arm because different overloads on the muscle-tendon structure can be caused according to their patterns over the ROM.

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“…The explanation for LFF in this circumstance has been that there appears to be a rightward shift in the forcelength relationship (6) due to increased compliance. If this was the case, then sarcomere length would be shorter at any given whole muscle length and the selective depression of force at low frequencies could be explained by the known length dependence of submaximal force (7,8). However, it has been shown that the apparent rightward shift in the force-length relationship is similar after isometric contractions and after eccentric contractions (9) and it has been suggested that this shift may be an artifact of the manner in which active force is calculated (10).…”

Section: Introductionmentioning

confidence: 99%

Low-frequency fatigue at maximal and submaximal muscle contractions

Baptista

Scheeren

MacIntosh

et al. 2009

Braz J Med Biol Res

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Skeletal muscle force production following repetitive contractions is preferentially reduced when muscle is evaluated with lowfrequency stimulation. This selective impairment in force generation is called low-frequency fatigue (LFF) and could be dependent on the contraction type. The purpose of this study was to compare LFF after concentric and eccentric maximal and submaximal contractions of knee extensor muscles. Ten healthy male subjects (age: 23.6 ± 4.2 years; weight: 73.8 ± 7.7 kg; height: 1.79 ± 0.05 m) executed maximal voluntary contractions that were measured before a fatigue test (pre-exercise), immediately after (after-exercise) and after 1 h of recovery (after-recovery). The fatigue test consisted of 60 maximal (100%) or submaximal (40%) dynamic concentric or eccentric knee extensions at an angular velocity of 60°/s. The isometric torque produced by low-(20 Hz) and high-(100 Hz) frequency stimulation was also measured at these times and the 20:100 Hz ratio was calculated to assess LFF. One-way ANOVA for repeated measures followed by the Newman-Keuls post hoc test was used to determine significant (P < 0.05) differences. LFF was evident after-recovery in all trials except following submaximal eccentric contractions. LFF was not evident after-exercise, regardless of exercise intensity or contraction type. Our results suggest that low-frequency fatigue was evident after submaximal concentric but not submaximal eccentric contractions and was more pronounced after 1-h of recovery.

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Length dependence of active force production in skeletal muscle

Cited by 345 publications

References 82 publications

Strength deficit of knee flexors is dependent on hip position in adults with chronic hemiparesis

Strength deficit of knee flexors is dependent on hip position in adults with chronic hemiparesis

Critérios mecânicos para progressão de exercícios de rotação interna e externa do ombro no plano sagital

Low-frequency fatigue at maximal and submaximal muscle contractions

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